This invention relates to a novel circuit breaker, and particularly an accessory contactor or a motor contactor which includes a module to limit or attenuate voltage peaks. The module is carried in a plastic casing which is housed in a recess of the circuit breaker housing side wall and is in electrical conduction with connecting rails of the contactor without being connected thereto in any fashion through the conventional coil connector screws.
The contactors of the type to which this invention is directed are known and are made in various shapes, sizes and designs. A distinction is made between AC-actuated and DC-actuated contactors. In order to attenuate voltage peaks generated when AC-actuated contactors are turned "OFF", and which may rise to a multiple of the rated actuated potential, it is normal to use RC modules (R and C denoting resistance and capacitance, respectively). In order to limit voltage peaks generated when turning "ON" DC-actuated contactors which may also reach a multiple of the rated actuation potential, attenuating modules are used, such as diode modules or varistor modules. The electric components of the modules are preferably cast in plastic and/or mounted in a separate case or casing defining a relatively small component of the overall circuit breaker. Common to all such modules is the fact that they are normally mounted on an outer end surface of the cover of a particular contactor/circuit breaker, and in most cases the modules include a foot which is inserted into an aperture of the contactor cover. Two flexible hook-up leads of varying length extend from each module to permit the module to be connected to the contactor coil. The latter is accomplished by connecting the hook-up leads of the module to the conventional coil connector screws and the associated coil terminals by being inserted into connection rail clamps against which the connector screws bear. In practice, serious difficulties are encountered by this arrangement because the connection rails or terminal clamps already include ordinary leads and is difficult/cumbersome to additionally connect thereto the hook-up leads of the module. Furthermore, because of the latter difficulty it is not infrequent for the module hook-up leads to become disconnected or to malfunction.
As regards DC-actuated contactors, there are difficulties if the hook-up leads of the module are interchanged with respect to the negative and positive terminals. Furthermore, aside from the unsightliness of the hook-up leads dangling from the contactor cover, the main drawback of this arrangement is the extra bulk created by mounting the modules atop the contactor covers. The latter requires that the module together with the hook-up leads and the coil terminal clamps be disassembled, and ultimately reassembled or refastened once again, at any time that the module must be changed, removed, or the contactor cover opened or closed relative to its housing. All of this is relatively cumbersome and leads to unreliability and product malfunctions.